<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>四则运算</title>
	</head>
	<body>
		<script>
			var num1 = parseInt(prompt("请您输入第一个整数:"));
			var ysf = prompt("请您输入运算符(1.+ 2.- 3.* 4./)");
			var num2 = parseInt(prompt("请您输入第二个整数:"));
			if(ysf=="1"){
				document.write(num1+num2);
			}else if(ysf=="2"){
				document.write(num1-num2);
			}else if(ysf=="3"){
				document.write(num1*num2);
			}else if(ysf=="4"){
				document.write(num1/num2);
			}
			else{
				document.write("请输入正确的值");
			}
		</script>
	</body>
</html>
